OP, This is a tough situation, especially for the kids (at that age), it always affects them in adverse ways. Hard to weigh out your children's best interest and your own state of happiness, hope you make the best decisions.
That said, this list that TIS posted is pretty solid, but should come with some warnings.
I went thru a brutal divorce & vicious coparenting situation for many years, so I'll just share from my experience. 1,3, & especially 4 stand out to me.
1-Lawyers can be the biggest $$$ suck in the whole equations, be careful in choosing and the amount of use. Best to learn about the legal process and be able to file things yourself, as I had to do when the $$ ran out after the 2nd court case, I had 6 divorce court dates.
3-Get a safe, put it in a secure location, and store away as much undocumented cash money as you can. Thinking you can rebound from a divorce quickly is naive to say the least, they're gonna take half of everything, then you'll have to pay alimony & child support. You're going to need it.
4-Parental alienation (this is a big one), you know your partner better than anyone here, is she the type that will hold that grudge for many years?, will she use those kids as a weapon against you? Try to relocate far away to put distance between and your kids? Will her overall hatred bleed into an environment that fosters contempt for you from your own children? Keep in mind that parental alienation sometimes leads to complete estrangement from your kids.
Sorry to be so gloom & doom about things but I've been thru it, and my situation was a worst case scenario. I suffered for many years and was left with a life that was not what I envisioned at this stage in my life.
If you can salvage your relationship thru psychology, counseling or dread game, by all means, but if it's at the point of no return, be strong, cause it's a tough road thru the divorce court system.